Proper punching form (And what happens when a little girl uses it)
by rex1011amit
Summary: Kirishima teaches Eri how to throw a punch. He regrets it very shortly afterwards. Cross-posted on AO3, second in a series of cute Eri one shots.


When Eri moved into the Class 1-A dorms, she was given a universal keycard, which allowed her to enter any room at the dorms, and a few at the school proper, at her leisure (provided she knocked first, of course), thus a fairly common sight among the students was for Eri to wonder around when she had nothing to do until she eventually decided on which room she wanted to enter that day.

Today being the room of one Eijirou Kirishima, who was busy breaking his head over the homework Cementoss left them at the end of the day when he heard a soft knocking on his door, followed by the even softer voice of class 1-A's little sister, "Uncle Kiri! Can I come in?"

Glad for any excuse to look away from his homework for even a moment, Kirishima looked up at his door with a toothy grin, "Sure!"

The little girl slide the keycard through the lock, and slowly opened the door until she could peer in with one eye to see Eijirou bent over his desk with a lot of books, "A-Are you busy? I-I can leave…"

"No no don't worry kiddo," Kirishima waved off her concern before it could sink too deep, "I was just about to take a break any way." He made a show of stretching his arms over his head and yawning with all his teeth, prompting the little girl to rush into his room with a skip in her step, "So, what're you up to?"

"Just walking around," She said easily looking around the room before hopping on his bed to sit, her legs swinging over the edge, "Mama and Papa are busy, so I was looking for something to do." Her eyes eventually settling on the punching bag set to one side of the room, "Uncle Kiri what's that?"

Eri's nickname for Izuku and Ochako pulled a chuckle out of him before he answered her question, "That's a punching bag, I use it to train."

"How?"

"Well…by punching it."

"Is it fun?"

Kirishima hummed, "I guess it is, helps me let out some steam." He sees her eyeing the bag more intently, smirking when he saw her legs swing a little faster, "Want to give it a try?" She snaps to attention, looking at him intensely before quickly nodding her head, "Alright, let me get you a pair a gloves."

Eri jumped off the bed, bouncing on the tips of her toes while Eijirou started digging for some gloves that might fit her, finally finding a pair that, while still large, didn't dwarf her hands too extremely.

After helping her put on the gloves they walked over to the bag, Eri standing in front of it while Kirishima stood to the side with a smile on his face, "Okay, go ahead! Throw a punch!"

Eri bounced excitedly one more time before closing her fist inside the glove as best she could, before pulling her arm back and letting out a cute little yell as she throw a clumsy little punch, her hand bending at the wrist when it hit the bag. Although she didn't seem to notice as she turned to the older boy for approval, only to see him looking at her with a bit of concern, "Did I do something wrong?"

Kirishima broke out of his gaze to get down on one knee so he could look her in the eye, "No you did nothing wrong Eri-chan!" He took hold of one of her gloved hands, "I was just worrying when I saw you hit the bag." He carefully moved her hand up and down, "See, when you hit the bag your wrist bent, which could get you hurt if you hit the bag hard enough," He lifted one hand and made a fist, "When you make a fist, you gotta lock your wrist so it doesn't move when you go for a punch."

Eri tried moving his hand like he did hers, failing to make it budge. She looked at her own, closing it into a fist more carefully, tightening it to lock her wrist, when Ejirou poked it a few times, and the hand didn't budge, she went for a punch again, this time with a little less force, her wrist staying straight when it hit the bag.

"Good!" Kirishima said with a smile, making Eri grin, "Okay now stand like-You're right handed right Eri-chan?" She nodded, "Right, like this," He put his left foot forward and his right foot back, and put up his fists just below his chin, his right arm a little behind his left, Eri eventually copying him, "Right! Now when you punch, "He mimed the movement, slowly so Eri could see him do it, "Shoot you're arm straight out and put your waist into the movement to give yourself a little more oomph."

They spent the next hour or so like this, until finally Eri managed to let out a perfectly placed punch, the bag swinging away slightly at the force of her blow, the girl jumping for joy at her success, "Uncle Kiri! I did it!"

"Yeah you did!" He was grinning from ear to ear with all of his teeth showing while giving her a fist bump, seeing her so excited to be able brought back memories from when he was younger and his dad taught him how to throw a punch, his grin diminished when a thought came to him of that time, and something important his father told him back then that he needed to pass on, "Hey, Eri-chan."

She stopped in her joyful bouncing to look at the suddenly serious Kirishima, "Yeah?"

"I need you to promise me something," He again went down on one knee and took one of Eri's hands out of a glove, holding it with both of his, "I want you to promise that you won't go around and punch people over every little reason,"

"Uncle Kiri I-"

"Let me finish," He said firmly but gently, Eri nodded and he went on, "That punch I taught you? Promise me you'll only use it to defend yourself, or to stop someone else from getting hurt, okay?"

Eri looked at him for a second before giving him her best serious look, "I promise."

Kirishima smiled a little, "Cool," He then grinned, breaking the tension, "Want a hug?" When she nodded with a smile he scooped her up with a spin, before setting her down, "As much fun as that was…I kinda need to get back to my homework," Eri nodded and went to go outside before Kirishima stopped her again, this time face a little nervous, "Also…don't tell your folks about this alright?"

"Why?"

"Because Uraraka will break me like painted glass." Is the thought going through his head, but he just says, "Don't want them to worry is all…"

Eri leaves and he goes back to his homework, and for a few days its business as usual at the dorms…until something odd happens. It started out rather innocently, in the common room with the rest of the class, Midoriya had just beaten Bakugou in a game and the blonde boy was throwing one of his usual rage fits…though granted one that was a bit louder than usual, on account of him having a few rather rough weeks before.

Eri was in the room with them so his yelling was free of cursing, but still it sounded like he might go a bit far if someone didn't step in to calm him down, but just when Kirishima was about to get up…the yelling stopped, followed by the sound of a body hitting the floor.

When Kirishima finally turned around, he saw Bakugou clutching his crotch while his face was lost somewhere between pained and confused. Next to him stood no one other then Eri, who was standing in a proper fighting stance, her right fist clenched.

Kirishima started to feel a chill running up his spine, something horrible was going to happen. But he wasn't sure what.

At once the class started whispering, starting with Jirou, "What just happened?"

Kaminari next, as quietly as he could, though he was visibly holding back from laughing, "Eri-chan just hit Bakugou in the grenades…"

Soon the whole class was whispering, those that weren't holding back laughter, while Eri looked around her, worrying her fingers as she realized she might have just done something bad, before she could speak up, probably to apologize, Katsuki's voice rose above the whispering, "Why the hell do my balls hurt?"

This question seemed to have awoken Midoriya from his shock, as he immediately pointed a finger to the prone boy, "Language! And Eri-chan," He turned to her a bit frantic, "Who taught you to do that!?"

It was only then that Kirishima noticed that Uraraka was oddly silent this whole time, her face blank as if she could not decide on how to react. The chill reached the back of his skull, some ancient instinct screaming at him to run, but his legs would not move.

Eri, for her part, tried to avoid Izuku's gaze, looking down to her feet, "Um…"

"Well," Tsuyu spoke up suddenly, catching everyone's attention, "She did say 'Riot Rush' when she punched him…"

Kirishima could feel his heart drop through the floor, looking fearfully at Uraraka as she slowly turned her head towards him, eyes cast in shadow and face twisted in rage, **"KIRISHIMA-KUN…."**

"Oh no."

(Kirishima spent the next hour or so running for dear life, an angry Mama Ochako hot on his tail,

**"WHO SAID YOU COULD TEACH HER THAT!?"**

"SOMEBODY HELP!"

Thankfully they ran into Aizawa, who was able to calm her down before things got too violent. Eri is forbidden from punching anyone, and Bakugou…keeps his distance for a few days…just to be safe.)


End file.
